Whether you’ve already adopted the cloud or considering migrating to a virtual environment, you’ve likely heard the terms ‘virtual machines’ and ‘containers’ in reference to software deployment. But what exactly are they, and which is best?
In this article, we’ve explained what virtual machines and containers are, and explored the key differences between the two solutions, to help you choose the right fit for your business.
What is a virtual machine?
A virtual machine (VM) is essentially a software-replica of a physical computer that runs on top of your existing operating system; a virtual version of your hardware that lets you install and run software as though you were on an actual machine.
It’s like a computer within a computer, and lets you, in effect, operate multiple machines within one piece of hardware. To provide a metaphor, your computer is a building, while each apartment is a virtual machine – and you can have multiple virtual machines within the same building, each completely isolated and independent.
Common use cases of virtual machines include:
- Disaster recovery: Operating from a virtual environment means you can access resources and software from anywhere, even if your hardware fails (you can access your virtual machine from other hardware, with the correct configuration).
- Software testing: Being able to run multiple virtual environments within a single piece of hardware allows you to isolate a testing space, where you can develop applications without impacting other VMs.
- Remote working: Working from a virtual environment within the cloud means you can access your workspace from anywhere, as long as you have an internet connection.
What is a cloud container?
A is a packaged set of components, which each work together to deliver a certain function. For example, a series of microservices that, when bundled together, deliver a specific version of programming. As opposed to a virtual machine, containers aren’t necessarily independent of each other, and instead work within the same environment.
Common use cases of cloud containers include:
- Software development: Because containers can be deployed with speed and efficiency, they’re incredibly useful for testing, developing, and advancing software.
- Scaling resources: The infrastructure of containers means scaling comes naturally, making them the ideal software solution for businesses hoping to meet demand.
- Machine learning: In much the same way that they facilitate speedy software development, containers are also often used to advance machine learning capabilities, through continual testing.
What are the key differences between a virtual machine and container?
We’ve looked at VMs and containers in isolation, but how do they compare when stacked side by side?
Resource allocation
One of the main differences between virtual machines and containers is the way each allocates resources. The former is like having multiple separate computers, each with their own CPU, memory, and storage, while the latter are all hosted within the same environment sharing pooled resources.
Scalability
Due to the infrastructure involved in creating containers, scaling up and down comes naturally. Simply add or remove resources, based on fluctuating workload and demand. Meanwhile, scaling with a virtual machine is a little more time-consuming, and you’ll often have to provision a new VM entirely.
Portability
Containers comprise of appropriately-packaged computing components that can be deployed with ease (and, importantly, without significant configuration changes). This means you can move your components between different virtual settings, such as various cloud platforms – including between providers (i.e. AWS and Azure) – local machines, and testing environments.
Meanwhile, there’s a great deal more complexity involved in migrating a virtual machine, with the task taking much longer and requiring more resources than porting containers.
This is because they’re significantly larger, and you need to port your entire operating system. Of course, a full machine migration won’t necessarily be required on a regular basis, but you may find you need to move your virtual environment if you’re upgrading hardware, consolidating your infrastructure, or maintaining servers.
Security
Because a virtual machine is its own environment, completely isolated from other resources (with its own operating system, hardware, and network), it offers a high level of security and protection against threat and malware. Even if your hardware and host environment becomes corrupted, your virtual machine should remain unaffected and protected.
In contrast, containers don’t boast the same level of isolation, with resources obtained from a shared pool (hosted by your virtual environment). This means your containers are reliant on the security of the host operating system – and if that’s breached, your containers may be susceptible to attack. That said, of course, you can introduce additional security measures to mitigate risk, such as regularly scanning for vulnerability, verification processes, and container segmentation.
Cost efficiency
An important business consideration, cost may come into your decision making when choosing between containers vs virtual machines. Of the two, containers typically offer a more cost-effective solution (especially if you expect resource utilisation to fluctuate).
This is due to factors including:
- Resource utilisation efficiency: Because containers only use required resources, rather than full-service deployment, you can enjoy high efficiency i.e. you only use the services you need, when you need them.
- Operational costs: Because containers are typically quicker to deploy than virtual machines, and don’t require the same depth of management, you’ll often find your operational costs are lower.
- Energy consumption: Because you’re using fewer resources to deploy containers vs virtual machines, you’ll typically find your energy consumption is lower, which saves on spend.
However, it’s well-worth noting that the above doesn’t apply to all circumstances, and there are instances where a virtual machine would be a more cost-effective investment.
For instance:
- Isolation: If your applications need to be wholly isolated from other environments (this is where virtual machines excel).
- Security: Your application may have more stringent security requirements. Virtual machines naturally offer secure working environments, and it might cost more than it’s potentially worth to bring containers up to the same security standard.
- Existing infrastructure: You’re looking for ways to better-use underutilised hardware; in this case, you’ve already got the machine, so don’t need to make the otherwise-heavy initial investment (and it may even be cost-inefficient to let it go to waste).
Deployment speed
When we talk about deployment, we’re referring to the action of making a piece of software or application ready for use in the front-end. If deployment speed is an important factor when deciding between virtual machines vs containers, the latter wins outright.
Not only can containers be deployed in a matter of seconds (minutes on a slow day), but they’re also typically much more resource-efficient (you’re only using required components, rather than your full range of services). In contrast, virtual machines require lengthy configuration that can slow down the deployment process, with the exact time depending on application complexity, network speed, and server workload – though, in some circumstances, it can take hours.
Innovation and testing
Software testing is important for business development and growth, so it’s important to have a virtual environment that facilitates innovation. Both containers and virtual machines excel in this regard, in different ways.
On the one hand, containers offer great agility and flexibility, allowing you to quickly deploy components and enjoy accelerated experimentation (without overusing resources). And on the other, virtual machines provide a uniquely-isolated environment for testing complex applications; albeit the process being much slower, with longer test cycles.
Overall, as to whether you choose containers or a virtual machine depends on your business or project requirements; if you’re in the early innovation phases, containers might be most appropriate, while virtual machines allow for in-depth testing.
When should you use a virtual machine vs container
As you’ll have no doubt assessed from the above, there are a number of differences between containers and virtual machines. Of course, it doesn’t always have to be a case of choosing one or the other, and there’s often a time and place for each within your business.
When to use a virtual machine
You’ll likely benefit from a virtual machine if:
- You require full isolation between virtual environments, and the security that comes with it.
- You’re managing complex workloads that require specific configurations (such as fast storage or high memory).
- You’re running applications that require significant power.
When to use containers
Containers might be the best fit for your business if:
- You prioritise rapid testing and development.
- You’re looking to reduce infrastructure costs.
- Portability is a priority.
Alternatively, you might want to consider the benefits of both virtual machines and containers and opt for a combined, hybrid solution. This would allow you to identify the features of each that serve your business, and adopt an effective model centred around security, scalability, and innovation.
If this sounds like something you’re interested in, get in touch with our team of experienced cloud consultants who’ll be more than happy to answer any questions and provide bespoke advice. In the meantime, if you’re planning on migrating to a virtual environment, discover even more cloud advice over on our blog.
